A valve timing control apparatus is disclosed in JP H10-280919A. In the valve timing control apparatus disclosed in Paragraph 0029 and FIG. 1 of JP H10-280919A, for example, when a hydraulic fluid is supplied from an advance angle oil passage to an advance angle chamber for displacing the relative rotation phase in an advance angle direction, the hydraulic fluid in a retarded angle chamber is discharged from a retard angle oil passage to an oil pan through a one way drain control passage and a fourth port of a passage switching valve. Then, a pressure of the retard angle chamber becomes low and the relative rotation phase is displaced to advance the opening and closing timing of an intake valve.
However, in the valve timing control apparatus disclosed in JP H10-280919A, the drainage is conducted through a relative narrow port of the passage switching valve. Thus, when the hydraulic fluid is rapidly supplied to the advance angle chamber through the advance angle oil passage for displacing the relative rotation phase in the advance angle direction quickly, back pressure resistance occurs in the hydraulic fluid in the retard angle oil passage. Similarly, when the hydraulic fluid is rapidly supplied to the retard angle chamber through the retard angle oil passage for displacing the relative rotation phase in the retard angle direction quickly, back pressure resistance occurs in the hydraulic fluid in the retard angle oil passage. Accordingly, the rapid displacement of the relative rotation phase becomes difficult, and therefore responsiveness of the valve timing control apparatus is not sufficiently enhanced.
A need exists for a valve timing control apparatus which is not susceptible to the drawback mentioned above.